This is the 100 year anniversary of humans having an idea of what the heck the sun and all the stars actually are. If you had asked a leading astronomer in 1925 what the sun was, they would say that it's basically the same as Earth, but very hot.

In Cecilia Payne's doctoral thesis she was the first to say, from spectral data, that the sun was overwhelmingly made of hydrogen and helium.

It was later described as "the most brilliant PhD thesis ever written in astronomy".

https://en.wikipedia.org/wiki/Cecilia_Payne-Gaposchkin